The present invention generally relates to mobile radio communication systems, and in particular, to timing adjustments for packets transferred in a mobile radio communication system.
Mobile radio systems for providing interconnect services are well known in the art. Generally, interconnect services provide an interface to the public switch telephone network (PSTN) so that mobile radio subscribers can place and receive calls to and from conventional telephones. To support interconnect services, mobile radio systems typically include one or more transcoders (XCDRs) that convert pulse code modulated (PCM) traffic from the PSTN into a format suitable for transmission over a radio network, such as vector sum excited linear prediction (VSELP) format.
A problem with current mobile radio communication systems is that the transcoder output is not always synchronized with the operation of the base radio sites (BRSs) of the radio network. This can result in the loss of transmission packets, causing a degradation in audio and data quality. Moreover, the communication path delay between the XCDR and the BRS is not always constant, this variable delay can also result in further degradation of service quality. Accordingly, there is a need for a method and system of adaptively synchronizing packet transmissions between XCDRs and BRSs in mobile radio communication systems.